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Background The cabbage stem flea beetle (CSFB;Psylliodes chrysocephala) is an important pest of winter oilseed rape (OSR) crops in Europe. Damage is caused by adults feeding on young leaves and by larvae mining in the leaves and stems. The most common method to estimate the severity of CSFB larval infestation is by plant dissection, which is time consuming and labour intensive. Two alternative methods have been proposed: extraction of larvae from desiccating plants and counting the percentage of leaves with scars left by larvae on plant petioles. These methods are easy to implement and less time consuming than plant dissection but have not been properly validated. Results OSR plants were sampled in five different experiments and the two alternative methods tested; assessment of the total number of scars per plant as a predictor of the number of larvae was also tested. The number of larvae remaining in plants following various periods of desiccation was checked via plant dissection. We found that the desiccation method is efficient, giving reliable results after 7 days (76% of the total larvae extracted) with good accuracy in estimating the number of larvae per plant (±0.38 larvae per plant). The total number of scars also gives a reliable estimation of the number of larvae (r=0.76, accuracy of ±1.01 larvae per plant). Conclusion OSR plant desiccation and the total number of scars per plant are reliable methods to estimate CSFB larval infestation and will facilitate monitoring of this cryptic pest stage. © 2022 The Authors.Pest Management Sciencepublished by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

BACKGROUND\ud \ud The field ecology of the pollen beetle Meligethes aeneus and its damaging effects on oilseed rape crops are well understood. However, the flight behaviour of M. aeneus, in particular the drivers for migratory movements across the landscape, is not well studied. We combined three established methodologies; suction traps, vertical-looking radar and high-altitude aerial netting to demonstrate that M. aeneus fly at a range of altitudes at different points during its active season.\ud \ud RESULTS\ud By linking evidence of high-altitude mass migration with immigration of pollen beetles into oilseed rape fields, we were able to ‘ground-truth’ the results to characterise the seasonal movements of this pest across the landscape.\ud \ud CONCLUSION\ud We demonstrate that this novel combination of methodologies can advance our understanding of the population movements of pollen beetles and could provide an opportunity to develop predictive models to estimate the severity and timing of pest outbreaks.

The paper presents critical review of rapeseed production technology. Technological problems primarily include: precise and efficient fertilization, optimal sowing time for each hybrid, optimal plant density and crop protection.To achieve high yields of rapeseed seed, it is necessary to observe the basic agricultural management rules such as crop rotation and optimal time of applying cropping practices. Due to the hazards of excessive accumulation of pests and diseases, rapeseed should be grown in an “adequate“ crop rotation, returning to the same area only after 4-5 years.